ie 
308 MEETING OF THE BRITISH ASSOCIATION. 
In his review of science he gave a unity to his observations by 
dwelling on a particular aspect of its progress, which he thus ex- 
plains :— ; 
* One word will give you the key to what. I am about to discourse 
on; that word is continuity,—no new word, and used in no new sense, 
but perhaps applied more generally than it has hitherto been. We 
shall see, unless I am much mistaken, that the development of obser- 
vational, experimental, and even deductive knowledge, is either attained 
by steps so extremely small as to form really a continuous ascent ; OF, 
when distinct results, apparently separate from any co-ordinate pheno- 
mena, have been attained, that then, by the subsequent progress of 
science, intermediate links have been discovered uniting the apparently 
segregated instances with other more familiar phenomena. 
‘Thus the more we investigate, the more we find that in existing 
phenomena graduation from the like to the seemingly unlike prevails, 
and in the changes which take place in timo, gradual progress is, and 
apparently must be, the course of nature 
After the examination of the a sciences, he finds in Darwinism 
a striking illustration and proof of the continuity of natural pheno- 
mena, and gives the following botanical notes in support of his 
views : 
= SESS A. De Candolle, one of the most distinguished Continental 
botanists, has, to some extent, abandoned the tenets held in his ‘ Géo- 
graphie Botanique,' and favours the derivative hypothesis in his paper 
on the variation of Oaks; following up a paper, by Dr. Hooker, on the 
Oaks of Palestine, showing that some sixteen of them are derivative, he 
avows his belief that two-thirds of the 300 species of this genus, which 
he himself describes, are provisional only. 
“ Dr. Hooker, who had only partially accepted the derivative hypo- 
thesis propounded before the publication of * The Origin of Species 
through Natural Selection,’ at the same time declining the doctrine of 
special creation, has since then cordially adopted the former, and illus- 
trated its principles by applying them to the solution of various bo- 
tanical questions; first, in reference to the flora of Australia, the 
anomalies of which he appears to explain satisfactorily by the applica- 
tion of these principles ; and, latterly, in reference to the Arctic flora. 
* In the ease of the Arctic flora, he believes that originally Scandi- 
navian types were spread over the high northern latitudes, that these 
